Fire alarm system



Sept. 19, 1950 D COLEMAN FIRE ALARM SYSTEM 2 Sheets-Sheet 1 Filed May 26, 1947 Fig. I.

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Inventor 33 Dempsey Coleman Attorneys P 1950 I D. COLEMAN 2,523,097

FIRE ALARM SYSTEM Filed May as, 1947 I 2 Sheets-Sheet 2 52 4 49 Inventor Dempsey Coleman g mafia way HM latented Sept. 19 50 t UNITED STATES. P T NT OFFICE v aszaoav it V FIRE ALARM SYSTEM Dempsey Coleman, Fairbliiff, N. c. 7 Application May 26, 1947, Serial No. 750,532

1 zciaims. rouse-2s) This invention'relates to fire alarm systems and In the drawings:

it has for its mainbbject to improve fire alarm Figure 1 is a diagram showing the various parts systems such as usedin hotels, apartment houses of the system and their connections; and other structuresiwith a'number of separate Figure 2 is a similar diagram showing the deand guarded units which are provided with a tails of the connections; central alarm station having an indicator with Figure 3 is a partly sectional elevational view electricv warning signals automatically operated of the head of a chemical fire extinguisher provid- 'by fire responsivedevicesfin said units. w, ed with an automatically releasable stopper;

As a rule, the device located in the guarded Figure l is a detailed view of the twisted wires roomor unit for operating the electric warning used as a flame indicator; signal in the central alarm station consists either Figure 5 is a diagrammatic view of the therin a thermostat or in a fuse; 'both these devices mostatic device and of the relay controlling the have the disadvantage tha tthey can be adjusted 7 heavy amperage current. merely for relatively high temperatures and that Accordingito the invention the fire alarm sigthey are located at agiven point within the room nal is produced either by open wire loops II] or by to be guarded. In the event of a fire a relatively a thermostat 30. The wire loops l0 consist of long time may elapse until the point at which the two wires l2 provided with cotton insulation,

, device is mounted reachesthe critical temperawhich is waxed or impregnated with paraffin and ture. This time together with-the time necessary a pair of such wires are insulated from but are to reach the premises from which the alarm signal 0 twisted around each other as indicated in Figissuesand for bringing counter measures into ure {1. Thus an open loop is produced which is action, isxas'a. rule so long that such counterplaced around doors orfwindows or around other measures on a relatively small scale are no longer openings. If necessary it ,may run around the effective. room or other protected unit, say near the ceil- It is therefore aniobiect of the invention to ing and/or near the bottom. The insulated wires provide means for giving the alarmsignal atthe IZ'of the-loops Ill carry currents under low tenearliest possible stage and itis .a further object sion, forinstance under the tension of a battery .to provide, additional means for bringing the or of an'A. C. produced by means of a step down countermeasures automatically into effect at transformer. It has been found by experience i such an early stage. Theme'ans for operating 3 that the insulation of the wires will be kindled the countermeasures whichmay preferablycon and burn as soon as a flame reaches the wires, sist in a .chemical fire extinguisher maybe the even if the temperature produced by the fiame same means which operate the alarm signal or is comparatively low. Asflames developing in the maybe different means which are differently opcase of;fire invariably produce a draft and have erate'd and located. a tendency to reach the door or window, on ac- A further object of the invention consists in u t of the ressure which develops in a highly distributing the Said means a in arranging heated room and which produces a leakage, wires h in a such a Wtt that they are likely to laid around these openings will be reached by the erate in the initial stage wherever flames are flames Shortly after they originma The r originating. the premises o g Thgse A4 loops, as a matter of course are placed near other means may themselves either alone or in con- Openings. such as a fireplace an opening pro; junction with a temperature responsive device control the automaticoperation of the extingi gigs gz zgi igi g g gfi i i 22583: guishing means.

Further objects of the invention will be made N to be'prgvlded wllth thelse types of opemngs f apparentnrom the following detailed specifica- The Wlres used for 3 arm purposes y P 0 $1011 I Q i the customary one layer bell wire type w1th a 1 The invention is illustratedin thefaccompanys l l r of impr n d nd co ed cot on or ing drawings showing one embodiment or the ma b spe y pr d, s as t ma the insame. It is however to beunderstooid and will '50 su lation -more easily combustible. I The cotton be, clearto the expert skilled in' this art that the insulation burns almost completely without leav "same principles may be realized with modificaingl ashes once it has been kindled by a flame,

a tions of theembodime nt shown so thatsuch andupon disappearance of *the relatively thin modifications do not necessarily indicate a de v insulating layer the wires on account of the firm parture.from theinventio bo'twistingaround eachfother, come into electric contact, so that the loop is converted into a closed connection.

The loops of one room may all be connected in parallel and are branching off from two conductors l5a, b, 0, "5a, b, 0, one of which ([6) is connected with a common lead I! joined to a return conductor l8 which leads back to the battery I9 or other source of current.

The wires [5a, I5b lead to conductors 25 connecting them with the indicator board 28 of a central station 20 arranged at some central supervised point. with indicator signals and indicator relay sets 2|, by means of which an optical signal 23 (indicated as a lamp for example) may be given. The specific construction of the set and of the board is immaterial as any approved construction may be used; the specific construction of the central board signal sets shown in Figure 2 is without specific significance for the invention.

In addition to the optical signal 23 an acoustical signal such as a buzzer, an alarm bell 24 or the like may be arranged, preferably in a part of the circuit which is common to all indicator sets so that an acoustic alarm signal will be given simultaneously with every optical signal.

In addition to the loops H], II)" thermostats 30 are provided reacting, as is customary, to the temperature which is imparted to them by radiation or to the temperature acquired by the ambient air. These thermostats may either act heavy currents derived from a network 35; the

network may be identical with the power supp'ly network of the building. The relay 32 is pro- This indicator board is provided:

, melts at a low temperature.

independently or they may be operative convided with contacts 36 opening and closing circuit 33. The latter includes the chemical fire extinguisher 31.

As soon as the thermostat operates the chemical fire extinguisher which is of the type con training a liquid or gas under pressure and spraying either extinguishing gases or an extinguishing liquid or an extinguishing foam, is operated in a manner described below and therefore as .soon as a dangerous temperature is reached in the protected room countermeasures aiming at the fighting or extinguishing of the fire are initiated. These countermeasures will either extingu-ish the fire or keep it more or less in its initial stage until the room is reached by the personnel which has been alarmed by the signal on the switchboard.

The details of the connections and of the operating mechanisms are illustrated in Figures 2-, '3 and 5. Figure 3 shows the way in which the chemical fire extinguisher 31 is brought into operation. The said fire extinguisher has customarily a head 38 and is closed by a valve or a sleeve, in addition to the internal screw threads provided for fixing it on the head carries also external threads which serve to screw over it a cylindrical casing 44, carrying two terminals 45, 46 to which the wires of the heavy amperage circuit 33 controlled by relay 32 may be fixed. Between these terminals a fuse wire 48 is inserted, which becomes incandescent upon the passage of a short circuit current and melts after a short while. This wire extends across the casing 44 which is completely filled either with a combustible material, or with an alloy melting at a very low temperature, Thismaterial forms a stopper 49 arranged above the disk 40 and melts under the infiuence of the heat produced in the fuse wire 48 or is consumed by combustion.

The opening 5| of the casing 44 may be closed by a combustible disk 52 holding the stopper 49 in its position. The central portion of disk 40 likewise-may be made of an alloy material which The duct is thus freed when the stopper melts and drops and the liquid or gas under pressure contained in the extinguisher 31 is sprayed.

As explained it may be advisable to operate the fire extinguisher solely by means of the thermostat 30 or alternatively when the loop is short circuited or when the thermostat operates following a short circuiting of one of the loops l0, Ill. The connections for all these cases are shown in Figure 2' inthe compartments a, b, c. The last mentioned case is advisable because a short circuit in the loop may occur withoutany fire. On the other hand a thermostat may be adjusted to a much lower temperature'if it cooperates with a flame operated device.

The thermostat 30 shown in Figure 5 is preferably of the customary bellows type, expanding when heated with the air temperature. It operates a contact 54 which closes the relay circuit 33. The relay 32, in its turn, controls the circuit 55 carrying a current of relatively high amperage. The relay 32 may be dispensed with when the thermostat alonecontrols the current through the fuse, asindicated in compartment a in Figure 2.

r The diagram shown in Figure 2 will be readily understood from the foregoing description. A

short circuit in the loop due to the burning of the insulation of the wires [2, causes a current to flow from the source of current [9 (battery or low voltage secondary) through the relay 22 of the switchboard 2'8 and through lamps 23 to the conductor I5a in the compartment or room a. The circuit in this case is closed through the loop II) or II! when the insulation burns and connection is established over conductors [6a, l1 and [8 to the source of current or battery l9. This will light the signal lamp 23 and operate the indicators 29 and the acousticsignal 24.

The thermostat 30 in compartment a operates independently when the room temperature reaches .the desired limit. It closes the heavy amperage circuit 31a and thereby produces a melting or combustion of the stopper 48 of the extinguishing device 31.

In the compartment b the closing of the loop circuit I 0 or 1-0 produces an operation of the relay 32, by means of conductors 25b and l5b energized .in the manner already explained, over conductors I612, l1 and which are connected with return connector l8. The energization of relay 32 then closes the circuit 33 through the incandescent fuse wire melting the stopper of the fire extinguisher.

This operation will also occur when the thermostat 30 operates because the room temperature has risen to an undesirable degree, irrespective of v the closing of the loop. The circuit through the relay 32 is in this case closed over conductors 251D and 26, l1 and I8.

In compartment the ,fire extinguishing relay 32 is merely operated, if the loop and the thermostat are both operated .thus checking each others correct function. The circuit is again running from conductor 250 over the relay 32 p and the'thermostat contacts 54 to conductor 15c and over the loop or IE to conductor 16c and conductors "and I8.

It will bereadily understoodthat changes in it the constructive details or connections, will not affect the alarm system according to the invention.

Having described the claimed as new is:

1. Afire alarm system for the remote indicainvention, what is I tion of the outbreak of a fire in a protected area and for the operation of extinguishing means in said area, comprising a source of alarm current,

=an alarm circuit including at least one flame retion of the outbreak of a fire in a protected area and for the operation of extinguishing means in said area, comprising a source of current, an

alarm circuit, including flame responsive open sponsive open loop circuit, consisting of twisted insulated wires with inflammable insulation, said loop circuit being located in the above named protected area, and closing a branch of the said alarm circuit when exposed to a flame, a heat responsive thermostatic device in said protected area with contacts closing a branch of said alarm circuit when the said thermostatic device is operated, a fire extinguisher provided with a'temperature responsive fusible stopper in said .protected area, a fuse wire arranged withinsaid istopper adapted to melt said stopper when heated, a fuse Wire circuit, a relay having a winding arranged within said alarm circuit controlling the admission of current to said fuse wire and fuse wire circuit, anda source of heavy currents supplying said fuse wire circuit.

2. A fire alarm system for theiremote indicaloop circuits consisting of twisted insulated wires 'with inflammable insulation, said loop circuits being located in the above named protected area and forming parallel branches of the said alarm circuit, a heat responsive thermostatic device located in the aforesaid protected area with thermostat contacts arranged within a branch of the, alarm circuit, connected in series with the branches containing the loop circuits and therefore closing said alarm circuit jointly with one of the loop circuits, a fireextinguisher in said protected area provided with a temperature responsive fusible stopper, a fuse Wire arranged within saidstopper to melt the stopper when heated, afuse wire circuit,'a relay, having a Winding arranged Within the alarm circuit and controlling the admission of current to said fuse wire and fuse wire circuit, and means for supplying the last named fuse wire circuit with heavy current.

DEMPSEY COLEMAN.

REFERENCES CITED The following references are of record in the file of this patent: 

